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So here's what I'm wondering: since the protocol is fairly simple TXD & RXD serial data and the $50K tool can read and write to it, wouldn't someone have already documented BMW's secret commands to do the detailed diagnostics and emulate them on a laptop?

Quote:

Originally posted by KIRASIR
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The 50k machine can tell you things like which wire is broken in your engine harness and will do a complete emission system diagnostics while the Peake's tool will only display the BMW engine code

Though not part of the EPA's OBD II standard, the diagnostic read-outs used by dealership technicians are also read through the OBD II connector. These service codes show you such things as knock sensor operation, FI pulse width, ignition voltage, individual cylinder misfires, transmission shift points and ABS brake condition. There can be over 300 readings available, depending on the vehicle manufacturer and model. Vehicles vary in the readings they will support.

BMW is not required to provide the interface information beyound the EPA requirements.

BMW diagnostics connector has NOTHING to do with OBD-2 connector/standard. They are two completely different things. BMW dealerships never use OBD II port to look up diagnostic information since OBD II port was only implemented so that the BMW cars would comply with the emission requirements. You can look up basic things like spark advance, short/long fuel trims etc. but that's about it. The most useful thing OBD-2 connector is good for general public is to read generic OBD-2 codes and reset the CEL. You can't even use it for detailed data logging since the data rate is painfully slow.

BMW diagnostics connector on the other hand is located under the hood(ODB-2 is under the steering wheel) and uses a BMW proprietary protocol. I believe both OBD-2 protocol and BMW one use a "standard serial" link to transmit data packets. As far as I know the only company that "hacked" the BMW protocol is Peakes, although I wouldn't be surprised if the actual protocol is described somewhere in a "book" like SAE standards or similiar.

SL

Quote:

Originally posted by KC Ron Carter They allow the manufacture to determine what they provide.

Though not part of the EPA's OBD II standard, the diagnostic read-outs used by dealership technicians are also read through the OBD II connector. These service codes show you such things as knock sensor operation, FI pulse width, ignition voltage, individual cylinder misfires, transmission shift points and ABS brake condition. There can be over 300 readings available, depending on the vehicle manufacturer and model. Vehicles vary in the readings they will support.

BMW is not required to provide the interface information beyound the EPA requirements.

As near as I can tell, OBDII is primarily (exclusively?) a passive reporting tool with only the ability to reset fault codes.

As you pointed out KIRASIR, the BMW diagnostic has far more advanced reporting and extensive programming capability. The Peake tools however don't seem to allow much beyond fault reporting and simple resets. The Shark, on the other hand, does allow extensive programming, however only for engine performance values (& to top it off, only for a single VIN!).

I'd be really surprised if someone hasn't captured all the cool things the dealer can do via the diagnostic connector and built a software tool to do the same. The question remains: does it indeed exist, and if so, where???